title: Magnetic resonance imaging of clinically localized prostatic cancer.
abstract: OBJECTIVE
  We assess the accuracy of endorectal coil magnetic resonance imaging (MRI) for detecting tumor localization, capsular penetration and seminal vesicle invasion in clinically organ confined prostate cancer. We also evaluate intra-observer and interobserver agreement in interpreting MRI studies.
  
  
  METHODS
  MRI studies of 51 consecutive patients a mean of 61 years old with biopsy proved prostate cancer were retrospectively read twice by 2 radiologists in random order. Both radiologists marked tumor localization, capsular penetration and seminal vesicle invasion on standard tumor maps. These findings were compared with the histopathological results of radical prostatectomy specimens.
  
  
  RESULTS
  The overall accuracy of detecting cancer localization was 61%. The detection rate for cancer foci less than 5 mm. was only 5% but for lesions greater than 10 mm. it was 89%. There was 91 and 80% accuracy for detecting capsular penetration and seminal vesicle invasion, respectively. Sensitivity and specificity were 60 and 63, 13 and 97, and 59 and 84% for localization, capsular penetration and seminal vesicle invasion, respectively. Intra-observer and interobserver agreement ranged from fair to good (kappa coefficient 0.240 to 0.647).
  
  
  CONCLUSIONS
  Endorectal MRI seems to be better than previously reported for detecting seminal vesicle invasion and tumor foci in the anterior half of the prostate. Sensitivity in detecting minor capsular penetration of the tumor was low, which can probably be improved by methodological development. MRI may be useful for locating cancer foci in patients with high prostate specific antigen values but repeatedly negative biopsy findings.
authors.affiliation: Department of Radiology, Helsinki University Central Hospital, Finland.
authors.forename: S
authors.initials: S
authors.lastname: Ikonen
authors.forename: P
authors.initials: P
authors.lastname: Kärkkäinen
authors.forename: L
authors.initials: L
authors.lastname: Kivisaari
authors.forename: J O
authors.initials: JO
authors.lastname: Salo
authors.forename: K
authors.initials: K
authors.lastname: Taari
authors.forename: T
authors.initials: T
authors.lastname: Vehmas
authors.forename: P
authors.initials: P
authors.lastname: Tervahartiala
authors.forename: S
authors.initials: S
authors.lastname: Rannikko
mesh_terms: D000368:Aged; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D015588:Observer Variation; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000473:pathology; D012189:Retrospective Studies; D012669:Seminal Vesicles / Q000473:pathology; D012680:Sensitivity and Specificity